【作者】 范尊强；

【导师】 田彦涛；

【作者基本信息】 吉林大学 ， 控制理论与控制工程， 2004， 硕士

【摘要】 精密驱动机构在机械制造、光学加工以及航空航天等领域有着广泛的需求。近年来随着微电子技术、宇航、生物工程等学科的发展，对精密驱动技术提出了纳米级甚至亚纳米级精度的要求。传统的精密驱动机构主要采用机械式，由于存在间隙、多环节传动等原因，其运动精度、定位精度难以满足上述要求。由于压电体具有反应速度快、变形精度高的特点，因而成为近年来构造精密驱动装置的主要方式。通过比较和分析，压电材料在实现精密驱动上具有相当大的优势。二. 压电叠堆的位移输出特性压电叠堆是由多层压电陶瓷晶片叠加在一起构成的，电路上的并联、结构上的串联使它的压电效应更加显著，可以在不太高的电压下，稳定的位移输出较大的变形。但是由压电陶瓷叠堆构成的驱动器本身存在的位移迟滞制约了它的发展。压电叠堆的迟滞非线性属于非局部存储型(Nonlocal Memory)迟滞非线性，<WP=67>这是压电陶瓷固有的特性。其主要特点是：系统下一时刻的输出不仅取决于当前时刻的输入，还取决于输入的历史。压电陶瓷的迟滞环是不对称的，即上升轨迹和下降轨迹之间没有对称轴。三. 压电多自由度驱动器结构原理步进式的工作原理是根据自然界某些爬虫类动物爬行的方法而提出的，其驱动过程如下第一步，压电叠堆A得电伸长并顶紧轨道，形成箝位。第二步，压电叠堆B得电伸长。第三步，压电叠堆C得电伸长并顶紧轨道，形成箝位。第四步，压电叠堆A失电，A与轨道松开。第五步，压电叠堆B失电，B收缩。压电叠堆C失电，C与轨道松开。至此，驱动机构向右前进了一个“步”。 <WP=68>四. 驱动器电源设计为了保证压电步进驱动器稳定运行，要给其施加可变电压幅值的电压。因为机构的响应频率不高，所以电源的频响要求不高，但其冲放电电流必须足够大。驱动电压波形通过实验研究最终选取为6个动作的类梯形波。整个电源可自己单独工作，又可以与经由上位PC控制进行从动行为。电源分为几个模块：由单片机构成数字电路部分、电压放大和功率放大部分、高低电压供电部分、输入和输出装置和与上位PC机通讯部分等。电源电压的稳定性及精度直接会影响，压电驱动器的精密运动五. 驱动器控制方法设计及试验改善或者消除压电叠堆迟滞特性的方法在控制方式上可分为开环控制和闭环控制；在控制算法上，传统的PID算法及其变形占有很大的比例，还有前馈控制、神经网络控制、模糊控制等。实际应用的方法很多是以上某几个方法相结合。 本文根据传感器的类型采用了位移反馈，利用传统的PID算法对驱动器进行闭环控制。针对系统结构为大行程、多自由度无合适传感器形成闭环的特点，本文采用了建立MAP图的方法进行标定，通过大量实验特性了解的十分清楚，位移精度有了很大提高。压电型驱动器目前视国内外研究的热点，多自由度驱动器是新型的精密驱动器，具有多自由度、大行程的特点。本文提到的驱动器及其驱动控制方法，是通过多次试验、测量并总结改进后得到的研究成果，具有一定的理论及应用价值。更多还原

【Abstract】 Piezoelectric bimorphs are a special type of piezoelectric devices, and nowadays have been widely used as displacement transducers or actuators in precise submicron increments. Piezoelectric ceramics are effective actuation elements in numerous applications that require rapid response and/or ultra-high motion resolution. These applications include optical fiber alignment, mask alignment, scanning by a scanning electron microscope, high precision machining. These days engineering and scientist require high goal on precision of the actuators. Since most of the actuators are mechanical, they have many clearances and drive processes , the movement precision, precision positioning can’t be achieved.Piezoelectric ceramics have advantages of high resolution, high stiffness, quick response, and so on. They have become the main modes on precision actuators these years. Piezoelectric materials have many superiority on precision actuate.2. The output characteristics of MPA The MPA (multilayer piezoelectric actuators) is spliced by bimorphs. The bimorphs are parallel connection on the electric and in series on the structure. So the MPA can output large displacement and power while needn’t high voltage. And this piezoelectricity effect will be steady. Hysteresis is an input/output non-linearity with effects of non-local memory. That is, the output of the system depends not only on the instantaneous input but also on the history. The hysteresis curves of the Piezoelectric ceramics is asymmetrical namely the ascend <WP=70>and the descend contrail isn’t the same. 3. The principle of the multifreedom precision linear stepping actuatorThe principle of the more freedom precision linear stepping actuator bring out from the animals creep on the ground. The moving process of the actuator is:First, MPA A stretches and holds the parallel trajectory when the voltage rises;Second, MPA B stretches when the voltage rises;Third, MPA C stretches and holds the parallel trajectory when the voltage rises;Fourth, MPA A losses from the parallel trajectory when the voltage falls;Fifth, the voltage falls and MPA B shortens. The voltage falls and MPA C shortens and losses from the parallel trajectory. So the actuator walks one step forward. The upper figure shows the actuator can walks back and forth in a line. If two or more such an actuator integrated, the actuator can drive on more freedoms. <WP=71>4. The design of the power supply of the actuators The more freedom stepping actuators of piezoelectric ceramics is a precision driving mechanism. So the requires on the power supply of the actuators will be strict. The output voltage must be very smooth and the charge and discharge current also must be enough. The actuator need special wave to drive it. We elect the trapezium wave and its ascending edge is similar to the letter “S”. The power can work alone or controlled by PC from RS232.The power supply of the actuators which is composed of MSC-51 single chip computer、DA converter、power supply、power amplifier、and communication part.The power supply of the actuator must be reliable, in order to make the actuators move in precision.5. The control of the actuators and the experiments Some papers have proposed the hysteresis model of piezoelectric ceramics, ferromagnetic materials and shape memory alloys. One approach to modeling hysteresis non-linearity, based upon the direct displacement feedback, PID in tradition is widely used. Another is to create a MAP to demarcate the actuators. Similarly, someone employ the Preisach model to compensate for the tracking error of piezoelectric actuators, and a model-based feed-forward compensator. The precision linear stepping actuator in the paper is hard to controlled by feedback because of the large travel, more freedoms. Here we create the MAP to demarcate because of sensor equipments. The precision actuator has a good performance proved by many experiments.Many institutes and graduate schools study piezoelectric actuator. The precisi更多还原